1. Technical Field
The present invention relates to printing methods, printing systems, and storage media.
2. Related Art
In printing apparatuses such as an inkjet printer, an image to be printed is printed on a medium by alternately repeating a dot forming process for forming dots by ejecting an ink from a nozzle moving in a movement direction, and a carrying process for carrying a medium such as paper in a carrying direction, and arranging continuously in the carrying direction raster lines that are configured by a plurality of the dots arranged in the movement direction.
As printing modes, there are known “interlace printing”, “overlap printing”, “non-uniform overlap printing” and the like (refer to JP-A-2002-11859). In the “non-uniform overlap printing”, the number of nozzles used varies for each raster line. For example, the number of nozzles used for a certain raster line is two, but the number of nozzles used for a different raster line is three.
There is a case where a position of a dot formed by a nozzle is shifted in the carrying direction due to a manufacturing error of the nozzle. As a result, due to the shifting of the dot, there occurs a spacing in between the raster lines, and a stripe-shaped banding occurs. As a cause of banding in which this kind of variation in density occurs, there are other causes such as a carrying amount error or a curling of the printing medium.
With the non-uniform overlap printing, the banding due to variation in density can be suppressed in the raster line that has a large number of nozzles that are used for it. However, according to the non-uniform overlap printing, since there are mixed raster lines that have a different number of nozzles that are used for it, there is the case where banding caused by gloss occurs.